Show a notification when an ephemeral app consumes excessive disk space

chrome/browser/extensions/extension_storage_monitor.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_EXTENSIONS_EXTENSION_STORAGE_MONITOR_H_
+#define CHROME_BROWSER_EXTENSIONS_EXTENSION_STORAGE_MONITOR_H_
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "components/keyed_service/core/keyed_service.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+#include "extensions/browser/extension_registry_observer.h"
+
+namespace content {
+class BrowserContext;
+}
+
+namespace gfx {
+class Image;
+}
+
+namespace extensions {
+
+class Extension;
+class StorageEventObserver;
+
+// ExtensionStorageMonitor monitors the storage usage of extensions and apps
+// that are granted unlimited storage and displays notifications when high
+// usage is detected.
+class ExtensionStorageMonitor : public KeyedService,
+                                public content::NotificationObserver,
+                                public ExtensionRegistryObserver {
+ public:
+  static ExtensionStorageMonitor* Get(content::BrowserContext* context);
+
+  // Indices of buttons in the notification. Exposed for testing.
+  enum ButtonIndex {
+    BUTTON_DISABLE_NOTIFICATION = 0
+  };
+
+  explicit ExtensionStorageMonitor(content::BrowserContext* context);
+  virtual ~ExtensionStorageMonitor();
+
+ private:
+  // content::NotificationObserver overrides:
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
+  // ExtensionRegistryObserver overrides:
+  virtual void OnExtensionUnloaded(const Extension* extension) OVERRIDE;
+
+  static std::string GetNotificationId(const std::string& extension_id);
+
+  void OnStorageThresholdExceeded(const std::string& extension_id,
+                                  int64 next_threshold,
+                                  int64 current_usage);
+  void OnImageLoaded(const std::string& extension_id,
+                     int64 current_usage,
+                     const gfx::Image& image);
+  void OnNotificationButtonClick(const std::string& extension_id,
+                                 int button_index);
+
+  void DisableStorageMonitoring(const std::string& extension_id);
+  void StartMonitoringStorage(const Extension* extension);
+  void StopMonitoringStorage(const std::string& extension_id);
+  void StopMonitoringAll();
+
+  // Initially, monitoring will only be applied to ephemeral apps. This flag
+  // is set by tests to enable for all extensions and apps.
+  bool enable_for_all_extensions_;
+
+  // A lower threshold is set by tests.
+  int64 initial_extension_threshold_;
+  int64 initial_ephemeral_threshold_;
+  int observer_rate_;
+
+  content::BrowserContext* context_;
+  content::NotificationRegistrar registrar_;
+  scoped_refptr<StorageEventObserver> storage_observer_;
+  base::WeakPtrFactory<ExtensionStorageMonitor> weak_ptr_factory_;
+
+  friend class StorageEventObserver;
+  friend class ExtensionStorageMonitorTest;
+
+  DISALLOW_COPY_AND_ASSIGN(ExtensionStorageMonitor);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_STORAGE_MONITOR_H_